[Groxx]

"The Law" absolutely runs on "when did this piece of paper arrive at this location". I don't know about DCMA specifically, but yes, most cases where one actor claims another actor is doing something wrong require the reporter to follow specific steps or it's not valid.

[SeanLuke]

This is nonsense. Google cannot simply provide a fake or broken button and get away with it. If Google is required to provide a mechanism for reporting DMCA violations in a timely manner, and they do not, they're going to found liable no matter what kind of excuse they provide.

[Groxx]

The reporting buttons in Play make absolutely no claim that it's for DMCA violations. Because it's not for DMCA violations.

DMCA claims go elsewhere, e.g. mailing them a physical letter or going through their separate reporting system for legal violations: https://support.google.com/legal -> https://support.google.com/legal/contact/lr_dmca?product=goo... . And, honestly, I'd still trust physically mailing them over that form - mailed letters start legal time limits for actions in many (many!) cases, online methods rarely have court-tested equivalent protections.